Venezuela’s rival political authorities are trading accusations of relinquishing the country’s historical claim to a large swath of neighboring Guyana on the eve of ExxonMobil’s launch of offshore production there.

Venezuela’s executive vice president Delcy Rodriguez today released what she says is a months-old tape of Vanessa Neumann, the UK envoy of opposition leader Juan Guaido, discussing the territorial issue with one of Guaido’s advisers, Manuel Avendaño.

In the alleged recording, Neumann says that after speaking with the UK Foreign and Commonwealth Office, she recommends that the opposition should “drop the topic” of Venezuela’s claim to the territory of Essequibo in order to secure London’s political support. Guyana is a member of the British Commonwealth.

Rodriguez said the tape was made before Guaido’s 23 January 2019 declaration of an interim presidency that the UK and most Western countries have since recognized as Venezuela’s legitimate head of state.

She accused Neumann and Guaido of giving up Venezuela’s claim to the territory, where ExxonMobil will start production of 120,000 b/d of crude in March 2020.

In response to the accusations, Guaido’s putative foreign minister, Julio Borges, today blamed President Nicolas Maduro’s government of “giving away the Essequibo” and not defending the country’s interests at the International Court of Justice.

Another official close to Guaido say Maduro’s late predecessor Hugo Chavez effectively abdicated the claim in exchange for Guyana’s political support under Venezuela’s PetroCaribe subsidized oil supply program for neighboring countries.

The fresh row is unfolding just as Guyana is preparing its debut as an oil producer from a newly arrived floating, production, storage and offloading unit (FPSO), Liza Destiny.

Guyana’s foreign ministry could not be reached for comment.

ExxonMobil operates the 6.6mn-acre Stabroek block in Guyana with a 45pc stake. US independent Hess holds 30pc, and the remaining 25pc belongs to Chinese state-owned CNOOC unit Nexen. Production from the deepwater Stabroek block is forecast to reach 750,000 b/d in 2025.

The UK has not commented on the dispute. Neumann could not be reached for comment.

ExxonMobil has made a rapid string of oil discoveries on Stabroek. The Yellowtail-1 find recently expanded its estimated recoverable resources on the block to around 5.5bn bl of oil equivalent.

Among other potential Guyana producers are UK independent Tullow Oil, which spud its second well on the offshore Orinduik block last month, as well as US major Chevron, Italy’s Eni and Germany’s Dea.